import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        BigInteger a = new BigInteger(in.next());
        BigInteger b = new BigInteger(in.next());
        BigInteger t = new BigInteger(in.next());
        BigInteger m = new BigInteger("1000000007");
        BigInteger two = new BigInteger("2");
        BigInteger result = a.add(b).divide(two).modPow(t, m);
        System.out.print(result.toString());

    }
}